In boring holes in rock formations, a common practice is to use a bit attached to a drill rod and simultaneously rotate and percuss the bit into the rock. The various design parameters for such a bit include a geometry of the bit body to insure the bit's stability in the borehole and a surface configuration of the bit that allows ready removal of the cuttings past the bit and out of the borehole. Prior bits have used geometries that include a larger head portion followed by a necked portion attached to the drill rod. These bits often have problems with stability in the hole.
A prior art bit that uses a generally cylindrical shaped bit body is shown in U.S. Pat. No. 4,953,642. While this geometry is desirable for its stability in the borehole, the configuration of the bit surface has a plurality of lateral grooves to pulverize the cuttings in the borehole which can contribute to binding of the bit in the borehole and especially to raising the temperature of the bit. When the temperature of the bit rises too much, there is an increased risk that the carbides on the leading end of the bit body will pop out of the holes that they are pressed into. Furthermore, many drilling operators prefer the cuttings not to be excessively pulverized.
Thus, a need exists for a bit with a stable geometry but also with a surface configuration that allows cuttings to be readily removed past the bit body and out of the borehole without excessive pulverization or hindrance of the cuttings by the outside surface of the bit body.